The study evaluated the effects of partially replacing soybean meal with fermented feedstuffs on laying performance, egg quality, nutrient utilization and intestinal health in aged laying hens. As laying hens enter the later stage of production, their laying performance, nutrient utilization efficiency, intestinal function, and egg quality tend to decline. Although unconventional protein sources may reduce feed costs, their use can be limited by high fiber content and antinutritional factors. Therefore, the study evaluated the feasibility of using fermented protein feedstuffs as partial substitutes for soybean meal in diets for aged laying hens.A total of 1,008 54-week-old Hy-Line Brown laying hens were randomly assigned to seven treatment groups, with six replicates of 24 hens per group, in a 12-week feeding trial. The experimental treatments included a control diet and diets containing 2%, 4%, or 8% fermented soybean meal (FSM) or fermented miscellaneous meal (FMM; cottonseed meal and coconut meal at a 1:1 ratio) as partial replacements for soybean meal. The feed ingredients were fermented using a mixed culture of Bacillus, Saccharomyces, Lactobacillus, and Clostridium butyricum.Fermentation altered the nutritional composition of the feed ingredients, increasing the concentrations of certain amino acids and organic acids while reducing neutral detergent fiber (NDF) and acid detergent fiber (ADF). Dietary inclusion of 2% to 8% FSM also improved the apparent digestibility of dry matter and NDF and increased nitrogen retention compared with the control diet.In terms of laying performance, the 4% FSM group showed a higher laying rate and egg mass than the control group (P < 0.05), whereas egg weight and the feed conversion ratio did not differ significantly. However, dietary inclusion of 8% FMM decreased laying rate and egg mass and increased the feed conversion ratio compared with the control group (P < 0.05). These results indicated that the effects depended on both feedstuff source and dietary inclusion level.Egg quality analysis showed that 4% FSM increased albumen height, Haugh units, eggshell weight, and eggshell strength, while 4% to 8% FMM increased yolk color scores compared with the control group (P < 0.05).Regarding intestinal health, dietary inclusion of 4% FSM or 4% FMM increased jejunal villus height, the villus height-to-crypt depth ratio, and jejunal diamine oxidase (DAO) activity. The 4% FSM group also showed higher jejunal transepithelial electrical resistance (TEER) than the control group. The expression of tight junction proteins, including ZO-1,occludin, and claudin-1, was also increased in the 4% FSM and 4% FMM groups, suggesting improved intestinal epithelial barrier function. Furthermore, increased expression of the intestinal stem cell marker Lgr5 and the proliferation marker proliferating cell nuclear antigen (PCNA) was consistent with enhanced epithelial renewal. Overall, dietary inclusion of fermented feedstuffs, particularly 4% FSM, improved laying performance and some aspects of egg quality in aged laying hens under the conditions tested. These benefits were accompanied by improved nutrient utilization, intestinal morphology, intestinal barrier function, and markers of epithelial renewal.
- Lu, Z., N. Zeng, S. Jiang, X. Wang, H. Yan, and C. Gao. 2023. Dietary replacement of soybean meal by fermented feedstuffs for aged laying hens: effects on laying performance, egg quality, nutrient digestibility, intestinal health, follicle development, and biological parameters in a long-term feeding period. Poultry Sci.102(3),102478.
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